<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>demo</title>
</head>
<body>
  <script>
    const a = b => 1
    console.log(a())

    const c = b => 1 + b
    console.log(c(9))

    const d = b => ({data: b})
    console.log(d(9))
  </script>
</body>
</html>